The present invention generally relates to an ultrasonic probe which projects an ultrasonic wave onto a living human body and receives a wave reflected in the body, so that information related to the body can be obtained from the reflected wave. More particularly, the present invention is concerned with an ultrasonic probe having a piezoelectric element.
Recently, a diagnostic method using an ultrasonic probe has been to be practically used. An ultrasonic probe is inserted into a part of a living human body, for example, a blood vessel, and the inside thereof is scanned by an ultrasonic wave emitted from the ultrasonic probe.
FIG. 1A illustrates a first conventional ultrasonic probe, which has a piezoelectric element 102 supported by a rotating shaft 101. An ultrasonic wave emitted from the piezoelectric element 102 is deflected in a plane substantially perpendicular to a direction in which the ultrasonic probe is inserted into the human body.
FIG. 1B illustrates a second conventional ultrasonic probe, which has a reflection plate 104 supported by the rotating shaft 101. The piezoelectric element 102 is held stationary in the probe. The ultrasonic wave is deflected in the same way as that shown in FIG. 1A.
FIG. 1C illustrates a third conventional ultrasonic probe, which has a plurality of piezoelectric elements 105 arranged on a circumferential surface of a cylinder 103. The ultrasonic probe shown in FIG. 1C scans a plane substantially perpendicular to the direction in which it is inserted into the human body.
The first through third conventional ultrasonic probes, shown, respectively, in FIGS. 1A through 1C, do not have a visual field in front of the probe, that is, in the direction in which the probe is inserted into the human body. There is a need to emit the ultrasonic wave in the probe inserting direction and obtain information about the area in front of the probe. FIG. 2 shows such an ultrasonic probe. An ultrasonic probe 108 is inserted into a blood vessel 107 of a human body, and forwardly emits an ultrasonic wave. Then, the ultrasonic probe 108 receives a reflected ultrasonic wave, which has information about the area in front of the probe 108.
Normally, a blood vessel of a living human body has a diameter of approximately 3-10 mm. Some ultrasonic probes capable of forwardly emitting ultrasonic waves are known. However, such conventional ultrasonic probes cannot be produced in a size compact enough to be inserted into such blood vessels of living human bodies.